Fix Python version for Travis CI tests
Remove unnecessary group declaration causing conflicting IDs

Change-Id: I4efffcabd0abb20e9374ff1a236a6dc50ad4fb9a
diff --git a/.travis.yml b/.travis.yml
index ff701f6..0abbcea 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,3 +1,6 @@
+language: python
+python:
+- "2.7.13"
 sudo: required
 services:
   - docker